(17212161 - 1)/1720
At this site we maintain a list of the 5000 Largest Known Primes which is updated hourly. This list is the most important PrimePages database: a collection of research, records and results all about prime numbers. This page summarizes our information about one of these primes.
This prime's information:
| Description: | (17212161 - 1)/1720 |
|---|---|
| Verification status (*): | PRP |
| Official Comment (*): | Generalized repunit |
| Unofficial Comments: | This prime has 1 user comment below. |
| Proof-code(s): (*): | x42 : Broadhurst, Water, Leyland, OpenPFGW |
| Decimal Digits: | 6990 (log10 is 6989.2869323309) |
| Rank (*): | 90600 (digit rank is 1) |
| Entrance Rank (*): | 19088 |
| Currently on list? (*): | no |
| Submitted: | 11/2/2001 01:19:54 UTC |
| Last modified: | 3/11/2023 15:54:10 UTC |
| Database id: | 21501 |
| Status Flags: | Verify |
| Score (*): | 31.3291 (normalized score 0) |
Archival tags:
There are certain forms classed as archivable: these prime may (at times) remain on this list even if they do not make the Top 5000 proper. Such primes are tracked with archival tags.
- Generalized Repunit (archivable *)
- Prime on list: no, rank 119
Subcategory: "Generalized Repunit"
(archival tag id 194729, tag last modified 2025-09-11 16:37:14)
User comments about this prime (disclaimer):
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Verification data:
The Top 5000 Primes is a list for proven primes only. In order to maintain the integrity of this list, we seek to verify the primality of all submissions. We are currently unable to check all proofs (ECPP, KP, ...), but we will at least trial divide and PRP check every entry before it is included in the list.
field value prime_id 21501 person_id 9 machine Linux PII 200 what prp notes PFGW Version 20020311.x86_Dev (Alpha software, 'caveat utilitor') Primality testing 1936120266...2554146744 Running N-1 test using base 23 0652118541...2827011761 [N-1/N+1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 67 Running N+1 test using discriminant 83, base 4+sqrt(83) Calling N-1 BLS with factored part 3.09% and helper 0.11% (9.39% proof) (1721^2161-1)/1720 is Fermat and Lucas PRP! (924.580000 seconds) modified 2003-03-25 17:22:43 created 2003-01-08 19:08:05 id 64629
Query times: 0.0003 seconds to select prime, 0.0005 seconds to seek comments.
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